High intensity multiple automatic arc lamp



June 4, 1935. F A BERG 2,003,675

HIGH INTENSITY MULTIPLE AUTOMATIC ARC LAMP Filed Feb. 3, 1930 4 Sheets-Sheet l June 4, 1935. F. A. BERG HIGH INTENSITY MULTIPLE AUTOMATIC ARC LAMP Filed Feb. 3, 1930 4 Sheets-Sheet 2 June 4, 1935; F A', BERG HIGH INTENsITY MULTIPLE AUTOMATIC ARC LAMP 4 sheets;sh`eet 3 Mill www Filed Feb. 3, 1930 June 4, 1935. F. A. BERG l HIGH INTENSITY MULTIPLE AUTOMATIC ARC LAMP Filled Feb. 5, 1930 4 Sheets-Sheet 4 IIN ANN A Maya/"Hey Patented `lune 4, 1935 UNITED STATES PATENT OFFICE Frederick A. Berg, Chicago, Ill.

Application February 3, 1930, Seal No. 425,440

17 Claims.

This invention relates to an improved high intensity multiple automatic arc lamp, particularly adapted for motion picture projection, whereby a high eiiiciency is obtained from the source of light and passed through the film at great concentration for better projection Work.

This application constitutes a companion case to application Serial N o. 412,309, filed December 1, 1929, for Multiple high intensity hydraulic projection lamp machine, and one of the main objects of the present invention is to provide a still more eiiicient and readily operated device.

Still another important object of this invention is the provision in a projection lamp machine for motion picture work of a plurality of elliptical mirrors for gathering the light rays from a pair of arcs or sources of light positioned at the focal points of one of the mirrors, the carbons and the accompanying apparatus being positioned and supported in such a way that undesirable shadows and light obstruction is eliminated.

Another and still further important object of the invention is the provision, in an arc lamp for motion picture work, of means for readily removing and replacing carbons when burned out or broken, which means may, if necessary, be utilized while the machine is actually in operation.

Still another important object of the invention is the provision, in a motion pictureprojection lamp, of automatic means for directing the arc and feeding the carbons for the arcs, this automatic means being augmented by manually operated arc striking and feed means for both positive and negative carbons.

Other and further important objects of the invention will be apparent from the disclosures in the accompanying drawings and following specication.

The invention, in a preferred form, is illustrated in the drawings and hereinafter more fully described.

In the drawings:

Figure 1 is a side elevation of the improved projection apparatus of this invention, parts being broken away to show the interior thereof.

Figure 2 is an enlarged side elevation of the tubular support for the carbons, which tubular support extends through a suitable opening provided therefor in the center of one of the elliptical mirrors.

Figure 3 is a top plan View of the tubular support with the carbons positioned thereon.

Figure 4 is a rear View of the combination automatic and manually operated are striking device and also of the automatic feed for the carbons.

Figure 5 is a sectional view of the means for instantly positioning and releasing the negative carbons, this view being taken on the broken line 5 5 of Figure 3, looking in the direction indicated by the arrows.

Figure 6 is a side elevation of the outer end of the tubular carbon support illustrating the positioning and supporting of the positive carbons, and being in effect an extension of Figure 2.

Figure '7 is a top plan View of the apparatus shown in Figure 6, parts being broken away and shown in section, this ligure being in effect an eX- tension of Figure 3.

Figure 8 is a detail sectional view of one side of the construction shown in Figure 6, the section being taken on the broken line 8-8 of Figure 6, and looking ln the direction indicated by the arrows.

Figure 9 is a sectional view taken on the line 9-9 of Figure 8, looking in the direction indicated by the arrows.

Figure 10 is a sectional view of the line Ill-l0 of Figure 6, looking in the direction indicated and showing the operation of the carbon clamping elements in dotted lines.

Figure 11 is a detail side view of the reflecting prism for inspecting the arcs.

Figure l2 is a transverse view through a portion of the casing shown in Figure l and illustrating particularly the elliptical shape of the mirrors.

As shown in the drawings:

The reference numeral I 0 indicates generally the casing of the improved motion projection machine of this invention, having a multiple arc therein composed of positive carbons l2 and I3 and negative carbons I4 and l5 respectively.

In order that the multiple arcs will function properly, the reflecting-mirrors are made concave and elliptical as illustrated at I6 and Il respectively, each of the arcs being positioned at one of the foci of the smaller mirror, the con.- struction of the mirrors themselves and the hydraulic cooling thereof being more particularly illustrated in the companion case as identified above. The outlet and inlet pipes for the cooling water are shown in Figure 1.

In the present invention, one of the particular objects is to so support the carbons for the arcs and the are striking and carbon feeding mechanism that there will be a minimum of interference between the light rays emanating from the arcs and the mirrors themselves so that a greater plished.

lighting eiciency will result and a consequent maximum concentration of light through the lm aperture I8 will be effected.

The actual support for the carbons and their appurtenances comprises a steel tube or the like I9, the same being suitably covered with asbestos or other insulating material as best shown at 20. 'Ihis tube is positioned by means of a plate 2| and bolts 22 upon the rear wall 23 of the casing which rear wall is also lined with suitable insulating material 24, the wall itself being mounted so as to be readily slidable rearwardly on the rods 25 (Figure 1) mounted in the ball-bearing supports 26 whereby the entire equipment may be withdrawn rearwardly from the housing I for the purpose of repairs, replacements, adjust` ments or the like.

Positioned immediately above the supporting tube I9 is a pair of negative carbon feed screws 21 (Figures 2 and 3) which are operated in the usual manner through 28 connected to a motor drive or the like whereby a positive forward feed of the carbons is accomplished to compensate for the burning away of the material during the operation.

A solenoid 29 is provided, the same being electrically connected to the current carrying wires 30 for the negative carbons whereby the throwing in of the switch for the current will automatically shift the screws 21 and the related carbons I4 and I forwardly, thereby striking the arcs. This -is accomplished by means of a magnetic `rod 30 extending rearwardly from the solenoid, the same being pivotally connected to a lever 3|, the lowerhalf of which lever is broken and then hinged -together, at 32 whereby the downwardly extending bifurcated ends 33 may be pushed forward manually to complete the striking of the arc in the event that the solenoid does not function. This manual forward push is accomplished against the pressure of a helical spring 34 positioned against a washer 34a at the forward ends of the screws 21 whereby the carbons will be automatically returned to proper operating posi.- tion as soon as the arc is established.

Extending forwardly through the tube I9 is a pair of drive shafts 35 which have driving gears 36 positioned on their rear ends, these gears being likewise motor driven from any convenient source'of power preferably through motor driven gears 31, a similar set of gears 31a operating the gears 28, the rotation of the shafts 35 imparting a corresponding feed to the positive carbons I2 and I3 respectively. Current carrying wires for the p ositive carbons are illustrated at 38, (Figures 2 and 6), these being connected to currentcarrying rods 39 which are carefully insulated from the remainder of the apparatus.

In the event that a manual adjustment of the feed for either the positive or negative carbons isdesired, hand wheels 49 are provided mounted on the shafts 4I which shafts also carry the gears 42, these shafts being slidable for a short distance in and out of the Wall 23 whereby a rearward motion thereof will cause the gear 42 to mesh with the gears 28 whereby the position of the negative carbons may be adjusted independgears 36 whereby a manual adjustment of the position of the positivecarbons can be accom- It will be noted that the shafts 35 Iextend forwardly through the tube I9 to approximately the end thereof, and adjacenttheir outer ends, are tted with ber or mica gears 43, (Figures '1 and which insulate the shafts 35 at this point from any further portion of the apparatus, each of the gears 42 in turn meshing with a pair of drive gears 44, these gears 44 being integral with knurled duplex carbon feed rollers 45. These gear and feed roller elements are mounted on shafts 46 suitably supported in ball bearings 41 whereby consequent ease of operation is accomplished regardless of heating of these bearings which very often occurs owing to the amount of current carried through the carbon electrodes I2 and I3. Suitable complementary rollers 48 are provided, these rollers also having their outer faces knurled to provide a gripping contact with the carbons, and it will be noted that these rollers are likewise mounted in antifriction bearings 49.

The positive carbons I2 and I3 are positioned at a slight angle with respect to the tube I9, as in this way less of the light rays will be interfered with, and the bearing faces of the feed rollers 45 and 48 are formed in accordance with this angular positioning of the carbons so that a correct spiral feeding thereof will result, and this feed will be more positive on account of the fact that a full b earing surface is provided between the feed rollers and the adjacent surfaces of the carbons.

In order that the carbons themselves may be conveniently and readily removed and replaced when exhausted or broken an instantaneously operated gripping and release means is provided, this being illustrated in detail in Figure 5 for the negative carbons and in detail in Figure 10 for the positive carbons.

In Figure 5 is shown a spring-operated clamp for each of the carbons, this comprising a coordinated pair of gripping elements 50 and 5 I, the elements 58 being fixed and forming part of the support, and the elements 5I being pivotally mounted at 52 to the portions 50. coiled spring 53 is provided at each pivotal mounting point so that the movable elements are forwardly impelled rinto carbon gripping position as shown in the full lines in Figure 5. A socket 54 is provided in the top of each movable element 5I into which an operating pin 55 or the like may be inserted whereby the element may be forced outwardly against the tension of the spring 53, thereby immediately releasing the carbon for removal and replacement.

It will be noted that. the mounting for these whereby the alignment of the carbons themselves with respect to the remainder of the apparatus and to the positive carbons may be accurately adjusted.

It will be noted that the combination supporting, releasing and gripping means for the negative carbons are movable as a whole and fed forwardly along with the carbons by means of the feed screws 21, being carefully insulated, however, from the feed screws by means of double layers of mica or other insulating material as best illustrated at 58 in Figure 2. The adjacent set screws 56 are also carefully insulated, being positioned in the sockets 59 composed of insulating material.

The quick release and mounting mechanism for the positive carbons (Figure 10) is somewhat similar to that for the negative electrodes, this mounting, however, including the spiral rotating being mounted in the movable portion 60 of theY feed mechanism as heretofore described, the cooperating feed rollers 48 being mounted'in the shiftable housing 60 which is movable outwardly to release the carbons, this also being normally maintained in carbon gripping position by means of a coiled spring 6I and operated by means of a pin 62 which can be inserted into a socket 63 adjacent the bottom of the movable portion of the casing.

The current carrying connections for the positive carbons (Figures 6 to 8) consist of electrodes 64 and 64a composed of nickel or some other noncorrodible alloy or metal which closely contact with the carbons I2 and I 3, each of the electrodes 64 having a socket 65 formed in the rear face thereof into which projects a pin 66, the pin carbon gripping and feeding mechanism. It will be noted that the pin 66 is carefully covered with insulating material 61 so that no current will be carried from the electrodes 64 to the carbon feed mechanism or its associated parts. These electrodes are forced into carbon gripping position by means of coil springs 68 as best shown in Figure 6. Thus, the action Iof the`elements 60 and 64 is unitary.

In order that the positive carbons may be kept properly aligned, thereby insuring Ia. proper operation of the arc, a support is provided for the rearwardly extending ends thereof, this support comprising a pair of bracket members 'l0 (Figure 9) fastened to but insulated from the tube I9, each of the bracket members 'I0 having mounted therein set screws 'II whereby the relation of the carbons with respect to the brackets and with respect to the feed and gripping elements and the electrodes may be accurately determined. It

will be noted that the tubing at this point includes ball bearings I2 for the outer ends of the shafts 3B, these bearing elements being carefully insulated from the interior of the tubing by means of a layer of mica or the like 13.

Allowance is made for inaccuracies and inequalities in diameters of the carbons, particularly with respect to the relationship between the gripping and feed members 60 and the currentcarrying electrodes 6l by so positioning the pin 86 in the opening 65 in the electrode 64 that theV pin will have considerable lost motion in the larger opening 65 whereby a positive contact between the electrode 64 and the carbon I3 will be effected regardless of any differences in diameter between the carbons at this point and at the point where the feeding and gripping elements contact therewith. It will be noted that the electrodes M and their appurtenances are carefully insulated from the supporting shaft I9 by means of layers of mica or the like 14.

A Ventilating motor and fan 'I5 is provided in the top ofthe casing I I, this being regulated and controlled by a damper 'I6 and a clean-out tube 11 is also provided `adjacent the motor and fan whereby the interior of the casing may be conveniently cleaned, this portion of the device, however, having been described in more detail in the companion case as heretofore described.

Mounted in the top of the housing I0 is a pair of reflecting prisms 18, one on each side thereof whereby the condition of the arcs may be readily inspected at all times, each of the prisms being triangular in cross-section as illustrated, and having its rear face 19 silvered to form a reflecting surface whereby the light rays are directed outwardly to the observer's eye. Pivotal points I0 areprovided at the sides of the prisms so that lthey can be readily tilted, thereby affording the opportunity for proper and instantaneous adjustment of the prism itself with respect to the relation between the observer's eye and the arc. A quadrant-shaped housing 8| in each prism is provided so that the same is capable of being readily tilted, a pivotal point 80 being frictionally mounted so that the desired positioning of the reflecting prism will be always maintained. A shelf I2 is provided for supporting the motor for driving the gear wheels, and the solenoid 29 is held in position by means of a strap 83.

It will be evident that herein is provided a high intensity automatically operated multiple arc lamp for motion picture projection work which, in addition'to providing an amount of available light far in excess of that produced by present devices, will have included therein an .automatically operated manually augmented ,feed

for the carbons together with simple yet efficient adjustments therefor, while at the same time providing for a practically instantaneous removal andlreplacement of one or both of the carbons, it being possible to immediately replace one carbon while the machine is being operated from light produced by the other set of carbons. Further, the device either automatically or manually compensates for irregularities in the carbons themselves and is so constructed as to eliminate overheating of the bearings and consequent undesirable sticking of the feed mechanism.

I am aware that many changes may be made, and numerous details of construction varied throughout a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than as necessitated by the prior-art.

I claim as my invention:

1. A multiple high intensity arc including an elliptical reflecting focusing mirror, the arcs being positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof.

2. A multiple high intensity arc including an oval rimmed elliptical reflecting focusing mirror, the arcs being positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, the negative feed connected with a quick release gripping means for the carbons.

3. A multiple high intensity arc including an oval rimmed elliptical reflecting focusing mirror, the arcs being positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, the positive feed including a quick release gripping means for the carbons.

4. A multiple high intensity arc including' a concave reflecting focusing mirror, the arcs beand mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and they positive carbon feed drive extending inside the Atube to the outer end thereof,

the positive feed including a quick release gripping means for the carbons, and also including gripping electrodesfor the carbons.

5. A multiple high intensity arc including an elliptical reflecting focusing mirror, the arcs being positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, together with a manual feed adjustment-for the carbons.

6. A multiple high intensity arc including an elliptical reecting focusing mirror, the arcs being positioned at the two focal points of the mirror and vmounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, the negative feed connected with a quick release gripping means for the carbons, together with an individual manual feed adjustment for both sets of carbons.

7. A multiple high intensity arc including an elliptical reflecting focusing mirror, the arcs being positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said supfport'comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative'carbn feed positioned outside the tube and the positive carbon feed drive extending inside the'tube to the outer end thereof, the negative feed connected with a quick release grippingI means for the carbons, together with van individual manual feed adjustment for the carbons, said feed adjustment comprising a hand wheel and gears, said gears being shiftable into meshing relation with the feed gears for either the positive or negative carbons. j 8. `A multiple high intensity arc including an elliptical reflecting focusing mirror, the arcs being positioned at .the focal points of the mirror and mounted on a supportvprojecting through an opening in the center of the mirror, said support comprising'a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, and automatic means for striking the arc between the carbons, said automatic means including a solenoid in the current carrying circuit for the arcs.

10. A multiple high intensity arc including an elliptical reecting focusing mirror, the arcs being positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, and automatic means for striking the arc between the carbons, said automatic means including a solenoid in the current carrying circuit for the arcs, and a system of levers connected with the solenoid for feeding the negative carbons forwardly into contact with the positive carbons upon closing of said circuit.

11. A multiple high intensity arc including an elliptical reecting focusing mirror, the arcs being positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, and automatic means for striking the arc between the carbons, said automatic means including a solenoid in the current carrying circuit for the arcs, and a system of levers connected with the solenoid for feeding the negative carbons forwardly into contact with the positive carbons upon closing of said circuit, and a manually operated arc striking element in conjunction with said automatically operated mechanism.

l2. A multiple high intensity arc projector including an elliptical reflecting focusing mirror, the arcs including carbons positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, and automatic means for striking the arc between the carbons, said automatic means including a solenoid in the current carrying circuit for the arcs, and a system of levers connected with the solenoid for feeding the negative carbons forwardly into contact with the positive carbons upon closing of said circuit, and a manually operated arc striking element supplementing said automatically operated mechanism, said manually-operated arc striking element comprising a hinged connection in the solenoidally operated lever, said hinge comprising a one way operation for the solenoid impulse but allowing of a manual operation thereof independently of the solenoid.

13: A multiple high intensity arc projector including a plurality of elliptical reflecting focusing mirrors, the arcs including carbons positioned atthe focal points of one mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, automatic means for striking the arc between the carbons, said automatic means including a solenoid in the current carrying circuit for the arcs, a system of levers connected with the solenoid for feeding the negative carbons forwardly into contact with the positive carbons upon closing of said circuit, and a manually operated arc striking element in conjunction with said automatically operated mechanism, said manually-operated arc striking element comprising a hinged yconnection in the solenoidally operated lever,

said hinge comprising a one way operation for the solenoid impulse but allowing of a manual operation thereof independently of the solenoid, together with the resilient means for automatically returning the negative carbon to proper arc maintaining position after the arc is struck.

14. In a carbon` arc lamp, means for instantaneously releasing the carbons, said means comprising a spring-impelled carbon gripping element, said carbon gripping means including automatic feed means for the carbons, said automatic feed means comprising a drive shaft, knurled feed wheels for the carbons and gear connections between the drive shaft and the knurled feed wheels, and current-carrying electrodes for the carbons, said electrodes being formed of laterally separable parts mounted adjacent to and operable with the carbon gripping and releasing means, and pin and socket connections between the carbon gripping and releasing means and said electrodes.

15. In a carbon arc lamp, means for instantaneously releasing and replacing the carbons, said means comprising a spring-impelled carbon gripping and positioning element, said carbon gripping and positioning means including automatic feed means for the carbons, said automatic feed means comprising a drive shaft, knurled feed wheels for the carbons and gear connections between the drive shaft and the knurled feed wheels, and current-carrying electrodes being formed of laterally separable parts for the carbons, said electrodes mounted adjacent to and operable with the carbon gripping and releasing means, and pin and socket connections between the carbon gripping and releasing means and said electrodes, said pin and socket connections including provision for lost motion between the electrodes and the carbon gripping elements.

16. A multiple high intensity arc projector including a casing, an elliptical reecting focusing mirror, the arcs including carbons positioned at the focal points of the mirror and mounted on a support projecting through an opening in the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the nega.- tive carbon feed positioned outside the tube and the positive carbon feed drive extending inside the tube to the outer end thereof, and automatic means for striking the arc between the carbons, said automatic means including a solenoid in the current carrying circuit for the arcs, and a system of levers connected with the solenoid for feeding the negative carbons forwardly into contact with the positive carbons upon closing of said circuit, and a manually operated arc striking element in conjunction with said automatically operated mechanism, said manually-operated arc striking element comprising a hinged connection in the solenoidally operated lever, said hinge comprising a one way operation for the solenoid impulse but allowing of a manual operation thereof independently of the solenoid, together with resilient means for automatically returning the negative carbon to proper arc maintaining position after the arc is struck, the entire mirror and carbon assembly being slidable forwardly and rearwardly as a whole from the casing.

17. A multiple high intensity arc projector including a casing, an elliptical reflecting focusing mirror, the arcs including carbons positioned at the focal points of the mirror and mounted on a support. projecting through an openingin the center of the mirror, said support comprising a tube and carbon supporting and feed means mounted in conjunction with the tube, the negative carbon feed positioned outside the tube and the positive carbon feed drive extending Vinside the tube to the outer end thereof, and

automatic means for striking the arc between the carbons, said automatic means including a solenoid in the current carrying circuit for the arcs, and a system of levers connected with the solenoid for feeding the negative carbons forwardly into contact with the positive carbons upon closing of said circuit, and a manually operated arc striking element in conjunction with said automatically operated mechanism, said manuallyoperated arc striking element comprising a hinged connection in the solenoidally operated lever, said hinge comprising a one way operation for the solenoid impulse but allowing of a manual operation thereof independently of the solenoid, together with resilient means for automatically returning the negative carbon to proper arc maintaining position after the arc is struck, the entire mirror and carbon assembly being slidable forwardly and rearwardly as a whole from the casing, and water-cooling means for the mirror. FREDERICK A. BERG. 

